Yahoo hack warning: What happened and should you be worried?

How could someone forge a cookie after stealing the source code? Did yahoo use a hardcoded private key in the code? Then any developer at yahoo could have broken into an account. That cannot be right.

"After disclosing two distinct hacks late last year, one of which implicated a billion users, Yahoo ..."

This is a weird place to use implicated as it makes the reader think those billion users are to blame for the hack. If that's true, it's a human-scale DDOS - no IoT devices needed.

I don't think it's a new hack it's just that the internal investigation has lead to more findings of the already talked about cookie hack: https://www.tripwire.com/state-of-security/featured/more-yah...

Remember that if you deleted your account the last time a breach was reported, DO NOT attempt to login to that account to check, as this will reset the decativation window of 90 days before permanent deletion.

I made that mistake last time, "deleted" my yahoo account when there was a breach, promptly forgot about doing that, then about 75 days later another breach was announced, so I logged in to "delete" my account....now I have to wait another 90 days before it's gone.

Has anybody ever seen Y! Confidential link pop-up in the bottom right corner of some Yahoo! articles which seemed to redirect to an internal corporate site? It came and went away at least a dozen times and in some instances it stayed for days.

Yahoo has been useless to me and others for years. It's just a holding company for Ali Baba, that also has an email service and a Japanese website.

I wonder how many people got that "a forged cookie may have been used" email. I suppose they're sending it even if the chance is remote

Dear Yahoo user,

We are writing to inform you about a data security issue that may involve your Yahoo account information. We have taken steps to secure your account and are working closely with law enforcement.

What happened?

In November 2016, law enforcement provided Yahoo with data files which a third party claimed was Yahoo user data. We analysed this data with the assistance of external forensic experts and found that it appears to be Yahoo user data. Based on further analysis of this data by the forensic experts, we believe that an unauthorised third party stole data associated with a broader set of user accounts in August 2013, including yours. We have not been able to identify the intrusion associated with this theft. We believe that this incident is likely distinct from the one that we disclosed on 22 September 2016.

What information was involved?

The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. Not all of these data elements may have been present for your account. The investigation indicates that the stolen information did not include passwords in clear text form, payment card data or bank account information. Payment card data and bank account information are not stored on the system that we believe was affected.

What we're doing

We are taking action to protect our users: We are requiring potentially affected users to change their passwords. We invalidated unencrypted security questions and answers so that they cannot be used to access an account. We are constantly enhancing our safeguards and systems that detect and prevent unauthorised access to user accounts. What you can do

We encourage you to follow these security recommendations: Change your passwords and security questions and answers for any other accounts on which you used the same or similar information used for your Yahoo account. Review all of your accounts for suspicious activity. Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information. Avoid clicking on links or downloading attachments from suspicious emails. In addition, please consider using Yahoo Account Key, a simple authentication tool that eliminates the need to use a password on Yahoo altogether.

For more information

For more information about this issue and our security resources, please visit the Yahoo Account security issues FAQs page available at https://help.yahoo.com/kb/index?locale=en_AU&page=content&y=.... Protecting your information is important to us and we are constantly working to strengthen our defences.

Yours sincerely,

Bob Lord Chief Information Security Officer Yahoo

Jeez, how do they still have a positive net worth? Like seriously, obviously their users & user data is worthless, they don't care about it getting stolen, nor do they seem serious about fixing their dilapidated, insecure systems.

This is just a case of poor management, if Google, Facebook, Twitter and others can figure out how to secure their sites, Yahoo can.

Is there a better source? That link just mentions it in the title and then plugs other articles they've posted for the rest of it.

EDIT: This seems like a better source: http://www.telegraph.co.uk/technology/2017/02/16/yahoo-hack-...